1. Technical Field
This invention pertains generally to the field of automated testing of electronic circuits. In particular, the invention provides a system for testing the functionality of circuit board controllers that control the operation of printing presses for printing high quality color images in newspapers.
2. Description of the Background Art
Newspaper editors and advertisers rely on modern printing presses to print color images of the highest quality in daily publications such as newspapers. The quality of printed color images is a function of the ability of a printing press to lay down with repeatable precision ink on paper.
In this regard, color registration and maintenance of ink quality are the two most important factors in determining how color image reproduction appears in a publication. In modern printing presses, a Dampening, Registration and Ink (xe2x80x9cDRINKxe2x80x9d) controller subsystem performs these tasks. The DRINK subsystem contains application-specific circuit boards that control basic printing press functions.
As a result of the continuous and intensive nature of the use of newspaper printing presses to produce a daily newspaper publication, color image reproduction quality periodically deteriorates, requiring printing press repair technicians to send out DRINK subsystem circuit boards to outside repair facilities for diagnosis and repair or replacement as a routine procedure in maintaining printing press color image reproduction quality.
However, experience has shown that frequently the circuit boards sent out for diagnosis and repair either do not actually need to be repaired (e.g., where color image quality deterioration is caused by a malfunction other than circuit board failure) or fail to be properly repaired.
While automatic general circuit board testing equipment is known in the art (see U.S. Pat. Nos. 4,965,516, 4,763,066 and 5,003,254 assigned to Huntron Instruments, incorporated herein by reference in their entirety), such equipment provides general diagnostics and individual point-to-point testing of multiple different circuit boards, and thus cannot test specific circuit board under load conditions experienced by the circuit boards. The simple general testing procedures employed by such equipment can lead to reduced circuit board repair success rates.
Application-specific testing of assembled circuits is also known in the art (see U.S. Pat. No. 6,038,520 assigned to ATI Technologies, Inc., incorporated herein by reference in its entirety). However, such testing requires a separate application specific testing entity for each assembled different assembled circuit. U.S. Pat. No. 6,324,485 assigned to New Millenia Solutions, Inc. (also incorporated herein by reference in its entirety) discloses equipment for testing integrated circuit devices in their native environment. However, such equipment requires the use of multiple native devices coupled to a test device in a configuration that recreates a native operating environment of the test device by precise timing control synchronization among the multiple native devices.
There remains a need in the art for a test system for specific DRINK circuit board controllers, wherein the test system is able to simulate actual operating conditions of a running printing press, in order to more accurately and quickly diagnose malfunctions in such circuit board controllers.
The present invention fulfills the existing need in the art by providing apparatus for testing functionality of a printed circuit board used to control operation of a printing press, including a plurality of input switches for providing to the circuit board test input signals simulating function control signals from a printing press control input, the function control signals controlling a plurality of functions of the printing press; a plurality of test loads simulating printing press loads for receiving from the circuit board output drive signals developed in response to the test input signals; and a processor for controlling operation of the input switches and for monitoring responses of the test loads in response to the output drive signals, whereby proper functionality of the printed circuit board in response to each of the plurality of function control signals is analyzed under simulated conditions of an actual operating printing press.